Earlier in January I made a post about the new VMware recertification policy. Those VCP’s who had reached the 2 year window had to recertify, using one of 4 options I mentioned in my previous post, by March 10, 2015 to maintain their VCP certification.

This week VMware posted a welcomed extension to the March 10, 2015 deadline, now extended to May 8, 2015. The extension was due to some technical issues prior to the deadline, and VMware wanting to give more time for VCP’s to recertify.

The other good news is that VMware want to thank those who acted early to meet the original deadline. These individuals will be able to upgrade their certification to VCP6 with 65% off the normal retail price. VMware will e-mail the discount details to those eligible directly, and migration exams must be taken by August 31, 2015.

Awesome news if you missed the March 10th deadline. This is your 2nd and final chance.

Share this:

Some of you may know by now that I am preparing for the VCP-NV certification. I have had a chance to complete the VMware NSX Technical Overview with Labs which was a nice starting point. I highly recommend the Overview with Labs if you do not have time to do the whole Install, Configure & Manage for NSX.

I am planning to take the VCP-NV exam in late February 2015 and am putting together the resources used, so keep visiting for those who are on the same journey.

Share this:

In 2014 VMware announced a new recertification policy for (VCP). If you are a VCP, you will need to recertify to maintain your VCP certification. In my opinion this is great as it ensures skills are current through longer product release cycles.

All VCP level qualifications will now expire as follows;

Certifications achieved before March 10, 2013 – must be recertified by March 10, 2015.

Certification achieved after March 10, 2013 – must be recertified within two years of that last VCP exam date.

Earn a new VCP certification in a different solution track. e.g VCP5-DCV take VCP6-Cloud.

Advance to the next level by earning a VMware Certified Advanced Professional (VCAP) certification. e.g VCP5-DCV take VCAP5-DCA exam.

Renew your current VCP5 DCV by completing a limited-time, streamlined delta exam. (Only available until 10 March 2015)

Based on new material between the vSphere 5.0/5.1 and vSphere 5.5 exams – you save hours of prep time.

Available online – you can take it from any location.

Far less expensive – you save money.

Free 1-hr course available

As you can see the best option before March 2015 is to take the delta exam. Be aware that if you let your certification expire you have to meet the course requirement again before you can do your exam.

Share this:

How can you decide which virtual disk type to choose? I had a number of questions last week around vSphere 5.x storage, VAAI & disk provisioning pros / cons. It makes total sense to take the opportunity and summarise it all here to answer the question.

Firstly we know that there are three types of Virtual Disks which we can choose from upon creation

Thin

Thick – Lazy Zeroed (Default)

Thick – Eager Zeroed

The disk type we select has a direct impact on the provisioning time, and in some cases, the performance of writes to the underlying storage.

To understand the differences we need to look at how the disks are created. Thick disks are fully allocated virtual disk files, where Lazy Zeroed are not zeroed out upon creation, and Eager Zeroed are zeroed out upon creation. Thin Disks in comparison are not yet fully allocated (grow as you go – save up front disk space) and are not zeroed out upon creation. Ultimately this means that Thin & Thick-Lazy disks have to do some additional work each time there is a new write operation i.e Thin Disk: Allocate Space+Zero, Thick-Lazy Disk: Zero.

After reading the above paragraph we could conclude that Thick Eager Zeroed disks are better for high I/O write workloads. A performance whitepaper also illustrates that whilst marginal, this was the case indeed. You can read the full performance paper here.

However, that is not enough to draw a conclusion just yet! It may have been the case in 2009 and in vSphere 4.0, but that was Pre-VAAI. In vSphere 4.1, VMware introduced the vStorage API for Array Integration (VAAI) which, if you are using a storage array that supports it, can offload intensive tasks to the array which therefore frees ESXi host resources to do other tasks.

Below are the key features of VAAI;

Full Copy / XCOPY / Extended Copy – Enables arrays to make full copies of data within the array without having the ESXi micromanage. Without VAAI, a ESXi host has to touch every single block during the copy like a broker. With VAAI, the host can off load the task to the array and asks it to handle it. The net result is that the copy is faster, as data does not need to go back up to the host and back down to the array, and you also save CPU, Memory & Network resource on the host. This also results in improved clones / Storage vMotions.

Block Zeroing / Write Same / Zero – Enables arrays to zero out a large number of blocks to speed up provisioning of virtual disks. Without VAAI, the ESXi host has to micromanage and repeatedly ask the array to Zero Out blocks. With VAAI, the ESXi host asks for a range of blocks to be zeroed out without supervision. The net result is you save CPU, Memory & Network resource on the host. This also mitigates some of the pre I/O write task latency of Thin / Thick-Lazy disk performance mentioned above.

ATS aka (Hardware Offloaded Locking) – A method of protecting the VMFS file system servicing the datastore. Without VAAI, when the ESXi host wants to write to the datastore it needs to lock the whole LUN via a SCSI reservation, which means that when you have multiple hosts accessing the same LUN you can have slower write operations / contention issues. With VAAI, the ATS locking mechanism is more granular and solves the contention issues you have using SCSI reservations. The net result is faster write operations to a datastore.

The full details of VAAI are summarised at a blog post here, I also suggest you read the whitepaper on VAAI here.

Finally to conclude this post and answer the question posed at the start of this post “How can you decide which virtual disk type to choose?”. The short answer is – It depends on the type of storage array you have and more importantly if you have implemented VAAI in your environment.

If you have implemented VAAI then performance differences are almost non existent, especially in environments with flash arrays. In which case, the decision comes down to the resource saving benefits of thin disks vs the predictable nature of thick disks and managing commitment.

Below is a summary of the pros & cons;

Share this:

At VMworld I had a go at the various labs. However, I was unaware that these can also be accessed after the event and throughout the year until recently. It is impressive to see so many live hands-on-labs available for public access. To access and register for Hands on Labs visit http://labs.hol.vmware.com. Below are a few I suggest you take a look at when you get a chance;

Introductory;

HOL-SDC-1410 – Virtualization 101

HOL-SDC-1406 – vCloud Suite 101

HOL-HBD-1481 – vCloud Air – Jump Start for vSphere Admins

HOL-SDC-1428 – VMware EVO:RAIL Introduction

Networking;

HOL-SDC-1424 – VMware NSX in the SDDC

HOL-SDC-1403 – VMware NSX Introduction

HOL-SDC-1425 – VMware NSX Advanced

HOL-SDC-1402 – vSphere Distributed Switch from A to Z

Storage;

HOL-SDC-1427 – VMware Software Defined Storage

HOL-SDC-1408 – VMware Virtual SAN 101

HOL-SDC-1405 – IT Outcomes – High Availability and Resilient Infrastructure

Share this:

A free utility from Star Wind utility which converts virtual disk files VHD/VHDX/VMDK by essentially cloning the virtual machine into the new format. This was handy for me today, needed to convert Win 2012 VHD for use in VMware workstation and then back again on my laptop.

The utility allows the selection of Thin/Thick destination formats, which is handy. Certainly worth a look at if you need a quick way to go between virtual disk formats.

Share this:

I was impressed when I saw this latest fling from VMware. This add-on provides detailed performance stats through the Web Client GUI, previously ESXTOP was only accessible through the command line. All flings are in a ‘experimental technical preview state’ but this is a handy one to see in the future.

If you have not used ESXTOP for performance stats before, I suggest you take a look at this fantastic guide on how to interpret them – click here.

Share this:

By default TPS has been enabled on ESXi hosts. TPS allows virtual machines to share identical memory pages and reduce the overall host memory footprint. This is achieved by allowing the hypervisor to scan at 60 minute intervals (default) for identical memory pages, reclaiming redundant copies and keeping a single memory page in physical RAM mapped to the virtual machines.

A recent article from VMware – Security Considerings and disallowing inter-Virtual Machine Transparent Page Sharing (KB2080735) acknowledges recent academic research that, under certain controlled circumstances, makes it possible to measure memory timings to try and determine a AES encryption key in use on another virtual machine running the same physical CPU. Whilst the probability of this occurring in the real world is low, VMware have taken the decision to disable TPS by default from future ESXi update releases as a security measure. However, administrators can turn it back on for the whole host or even individual virtual machines as needed manually.

Share this:

While VMworld officially starts tomorrow for most of us, today was the Partner Day where there are various sessions for them to understand the VMware solutions roadmap ahead.

I was there to get registered early and take a VCAP-DCD certification exam in CC5.2. I had initially underestimated how much floor space VMworld takes up. The test centre was a good walk away during which I also strolled into the the Hand-on-Labs section, which did look exciting indeed. I am looking forward to that tomorrow afternoon.

Registration was easy enough. I also received my backpack, badge, notepad, flyers, a water flask & 2 t-shirts throughout the day.